1. Field of the Invention
This invention relates to a high frequency switching device having an increased power handling capacity.
2. Description of the Related Art
A variety of semi-conductor devices are known to be suitable for use in radio frequency and microwave switching applications. These include PIN diodes, silicon bi-polar RF and microwave transistors, and field-effect transistors (FETs), all of which share the property of bias-voltage dependent impedances at high frequencies. Gallium arsenide (GaAs) FETs, especially, are advantageous for many RF and microwave switching applications because of their relatively high gate-source and gate-drain isolation, which permits use down to DC. When used in RF switches, GaAs FETs also have the advantage of small bias-line to RF port video frequency breakthrough, and they contribute very little noise.
Conventional RF and microwave transistor-based switches are limited, however, by their power handling capabilities. For example, present technology can provide FET junctions with a 20 volt peak breakdown voltage, which means that in a typical configuration having input and output port impedances of 50 ohms, the power handling capacity of the FETs will be limited to 4 watts. The present invention solves the power handling limitations of the conventional RF and microwave transistor-based switches.